Adding more needed development dependencies, bumping gem version

v2.3.0 - Ruby 1.9 support

v2.2.9.2 - Removed stupid S3 Deprec warning

Tagged v2.2.9.1

Version 2.2.9

v2.2.8: Restored the ability to assign nil to delete.

Fix for Rails 2.3

Version 2.2.6

Moved the matchers to fix issues with requiring

Processors are passed the attachment object, and more options are abl…

…e to be procs (url, path, and styles)